This invention relates to a new coating composition, coated articles formed therewith, and the method of application of the coating to substrates. The coating composition herein is particularly useful for glass mold surfaces. Surfaces coated using the compositions of the invention may be used as molds for metal casting, as forging dies, etc. Coatings of this invention not only provide lubricating abrasion resistant surfaces, but they also protect the substrates from oxidation or decarburization on long exposure to high temperatures.
The state of the art is indicated by the following U.S. patents, the disclosures of which are incorporated herein by reference U.S. Pat. No's. Seeman 3,783,013; Schanzer, 3,304,257; Woodburn, 2,685,542; Noble, 2,995,453; Norton, 3,495,962; Gardner, 2,618,530; Garatt, et al, 2,587,722; Nagel, 2,564,308; Garratt, 2,246,463; Birchall, et al, 3,702,774; Strater, 3,510,347; Lavik, 3,775,318; Hermann, 3,467,596; Woodburn, 2,685,539; Dean, 2,426,988; and Felice, et al, 3,637,412.
There has been a long standing problem in manufacturing or molding glassware because the mold surfaces used for this purpose had to be swabbed at frequent intervals by the machine operator with a swabbing compound (i.e., a protective material which also functions as a parting agent or lubricant). In order to avoid this problem the industry has long sought a permanent or semipermanent glass mold coating for the surfaces which contact the hot molten glass. Such a coating was desired in order to avoid the necessity of numerous swabbing compound applications and to increase production rates for the glassware, while at the same time assisting in reducing the number of glassware pieces produced which were defective by reason of contamination, flaws or dimensional faults. Accordingly, a main object of the present invention is to provide a new coating composition which eliminates frequent swabbing of glass molds.
Another object of the present invention is to provide a new coating composition for surfaces which contact hot glass such that the surfaces require only minimal, if any, swabbing for periods of 8 to 24 hours and longer.
Another important object of this invention is to eliminate the air pollution normally encountered in factories where oily lubricants are swabbed or sprayed on molds, forming dies, or on billets. By eliminating the smoke and vapors generated from oily materials health and fire hazards and atmospheric pollution is substantially eliminated.
Another object of the present invention is to provide a new coating composition and method for coating substrate surfaces useful in connection with metal casting or forging, to provide lubricity, long wear, thermal stability and protection against oxidation.
Another object of the present invention is to provide a new coated article which is highly useful in molding, casting, and/or forming operations.
Another object of the present invention is to provide a new method of preparing a mold surface capable of abrasion resistant usage at high temperatures.
Still another object of the present invention is to prepare a new coating composition which is itself applied at high temperatures and which forms relatively lubricious high temperature resistant coatings.
Other objects, features and advantages of the present invention will become apparent from the subsequent description and the appended claims.